Method of manufacturing metallic decorative member

Abstract

There is provided a method for manufacturing a metallic decorative member without a weld line at low cost including: starting injections of molten molding material into a cavity formed by a set of dies from a plurality of gates provided at the cavity; and stopping respectively the injections of the molten molding material from the plurality of gates at different times so as to make dynamic pressure of the molten molding material injected from one gate smaller than dynamic pressure of the molten molding material injected from the other gate at a position on which heads of flows of the molten molding material injected from the one and the other gates contact each other.

What is claimed is: 
     
       1. A method for manufacturing a metallic decorative member by using injection molding of injecting molten molding material including metal particles into a cavity formed by a set of molding dies from a plurality of gates provided to the cavity, the method comprising:
 starting injections of the molten molding material into the cavity from the plurality of gates; and 
 stopping respectively the injections of the molten molding material from the plurality of gates at different times 
 so as to make dynamic pressure of the molten molding material injected from one gate smaller than dynamic pressure of the molten molding material injected from the other gate at a position on which heads of flows of the molten molding material injected from the one and the other gates contact each other so that the metal particles at a contacting portion of the heads of the molten molding material are aligned at a surface of the molten molding material along a direction of movement of the molten molding material, 
 wherein the one gate is closed before the heads of flows of the molten molding material injected from the one and the other gates contact each other, and 
 the gates are arranged to have a distance between one pair of gates being shorter than the distances between the other pairs of gates. 
 
     
     
       2. A method for manufacturing a metallic decorative member according to  claim 1 , wherein:
 the cavity is formed into an annular shape, in which one portion of a circumference of the annular shape extends linearly along a chord of the circumference so that the annular shape is formed into a D-shape. 
 
     
     
       3. A method for manufacturing a metallic decorative member according to  claim 2 , further comprising:
 providing three gates at the cavity among which two gates are provided on an arc portion of the circumference of the annular shape, and one gate is provided at the chord portion of the circumference of the annular shape. 
 
     
     
       4. A method for manufacturing a metallic decorative member by using injection molding of injecting molten molding material including metal particles into a cavity formed by a set of molding dies from a plurality of gates provided to the cavity, the method comprising:
 providing the cavity formed into an annular shape, in which one portion of a circumference of the annular shape extends linearly along a chord of a circumference so that the annular shape is formed into a D-shape; 
 starting injections of the molten molding material into the cavity from the plurality of gates; and 
 stopping respectively the injections of the molten molding material from the plurality of gates at different times, 
 so as to make dynamic pressure of the molten molding material injected from one gate smaller than dynamic pressure of the molten molding material injected from the other gate at a position on which heads of flows of the molten molding material injected from the one and the other gates contact each other, 
 so that the metal particles at a contacting portion of the heads of the molten molding material are aligned at a surface of the molten molding material along a direction of movement of the molten molding material, wherein the one gate is closed before the heads of flows of the molten molding material injected from the one and the other gates contact each other, and 
 the gates are arranged to have a distance between one pair of gates being shorter than the distances between the other pairs of gates.